Huge undersea mountain found off Indonesia: scientists
May 29th, 2009 This aerial view shows new homes being constructed to the north of Banda Aceh

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This aerial view shows new homes being constructed to the north of Banda Aceh on the island of Sumatra in 2006. A massive underwater mountain discovered off the Indonesian island of Sumatra could be a volcano with potentially catastrophic power, a scientist said Friday.

A massive underwater mountain discovered off the Indonesian island of Sumatra could be a volcano with potentially catastrophic power, a scientist said Friday.

Indonesian government marine geologist Yusuf Surachman said the mountain was discovered earlier this month about 330 kilometres (205 miles) west of Bengkulu city during research to map the seabed's seismic faultlines.

The cone-shaped mountain is 4,600 metres (15,100 feet) high, 50 kilometres in diameter at its base and its summit is 1,300 metres below the surface, he said.

"It looks like a volcano because of its conical shape but it might not be. We have to conduct further investigations," he told AFP.

He denied reports that researchers had confirmed the discovery of a new volcano, insisting that at this stage it could only be described as a "seamount" of the sort commonly found around the world.

"Whether it's active or dangerous, who knows?" he added.

The ultra-deep geological survey was conducted with the help of French scientists and international geophysical company CGGVeritas.

The scientists hope to gain a clearer picture of the undersea lithospheric plate boundaries and seafloor displacement in the area, the epicentre of the catastrophic Asian quake and tsunami of 2004.

The tsunami killed more than 220,000 people across Asia, including 168,000 people in Aceh province on the northern tip of Sumatra.

Indonesia is on the so-called Pacific "Ring of Fire," where the meeting of continental plates causes high volcanic and seismic activity.

Scientists Use High-energy Particles from Space to Probe Thunderstorms
June 1st, 2009

(PhysOrg.com) -- Florida Institute of Technology researchers are trying to solve one of the great mysteries in nature: how thunderstorms make lightning. Because, in principle, lightning is a big spark it should behave like other sparks—like the ones created when we touch a door knob on a dry day. Scientists have accumulated evidence, however, that lightning sometimes behaves in very un-spark-like ways.

Lightning can start in regions of thunderstorms that have relatively low electric fields and, so, should create no sparks. Because lightning obviously is made by thunderstorms, scientists are left wondering what they are missing.

Three such scientists, Joseph Dwyer and Hamid Rassoul from Florida Tech and Martin Uman from the University of Florida, recently published a paper in the Journal of Geophysical Research titled, "Remote measurement of thunderstorm electrostatic fields." It describes their new technique to remotely measure thunderstorm electric fields on the ground.

By measuring small radio pulses made by cosmic-rays passing through these storms, they calculate that they can reconstruct the electric fields along the high-energy particle's paths. This could allow them to measure any lightning initiation pockets that might exist.

One idea is that thunderstorms generate big electric fields capable of making sparks, but those strong fields are localized in very small pockets—too small to be easily detected by the balloons and aircraft sent into thunderclouds to measure the fields. Although this seems reasonable, the problem has been how to test it. Indeed, for decades scientists have struggled in vain to find such pockets where lightning might be initiated.

"Cosmic-rays are high-energy particles from outer space that constantly rain down on our planet. They form a natural probe for measuring thunderstorms," explained Dwyer, professor of physics and space sciences, who is leading the research effort. "Thunderstorms are big, violent, and dangerous places. Cosmic-ray air showers allow us to study them from a relatively safe location on the ground."

"It's a daunting task to find these high field regions," explained Rassoul, professor of physics and space sciences. "Thunderstorms are large and the chance that a balloon would find its way into exactly the right place at the right time to catch lightning initiation is small."

This summer at the UF/Florida Tech International Center for Lightning Research and Testing at Camp Blanding, Fla., scientists are conducting experiments to search for these lightning initiation pockets. If successful, researchers will be closer to understanding lightning, a phenomenon that has mystified people for thousands of years.

Nearby compact galaxies may shine light on early star formationBy Ron Cowen Web edition : Tuesday, July 28th, 2009 Text Size Enlarge
Green peasThese portraits show a handful of rare, newly discovered galaxies, dubbed Green Peas because of their color and shape, that may be nearby analogs of distant galaxies undergoing an intense wave of starbirth. C. Cardamone, Sloan Digital Sky SurveyFor galaxies, it’s not easy being green. Most of them appear blue or red from Earth.

Indeed, after combing through an online image bank of 1 million galaxies, volunteers for the Galaxy Zoo project have found a mere 250 galaxies with an unusual, greenish color. These compact bodies, dubbed the Green Peas, are only about one-tenth the size of the Milky Way.

Now, a team of astronomers working with the volunteers has discovered that the Green Peas are hamming it up, forming stars at an enormous rate — about 10 times faster than the Milky Way. Spectra of the galaxies taken by the Sloan Digital Sky Survey — the source of the online images — indicate that the greenish hue comes from the glow of ionized oxygen gas heated by newborn stars, says astronomer Carolin Cardamone of Yale University.

High rates of star formation are common among some remote galaxies, which hail from the early universe, but the Green Peas are relatively nearby — between 1.5 billion and 5 billion light-years from Earth. The Green Peas may represent a closer, and therefore easier to observe, analog of those distant galaxies, report Cardamone and her colleagues in an upcoming Monthly Notices of the Royal Astronomical Society. The team has also posted the findings online at arxiv.org.

Galaxies from further back in time, when the universe was one-third to one-fourth its current age, forged many more stars than the typical galaxy of today does, notes Alice Shapley of the University of California, Los Angeles. That’s because these galaxies were pulling in a fresh supply of gas, the raw material for making stars, at a much higher rate than galaxies do today.

Those few galaxies that exhibit high star formation rates today are usually undergoing a rare, major merger with another galaxy. But the Green Peas appear to be loners, devoid of mergers. “If the Green Peas are really isolated systems, then the origin of their high star formation rates is a real mystery,” Shapley says.

Shapley says there are both similarities and differences between the Green Peas and the remote population, which are known as Lyman-break galaxies.

She agrees that the Green Peas appear to be distinct from typical, nearby star-forming galaxies and concurs that the Peas are forging stars at a prodigious rate similar to the Lyman-break galaxies. However, these remote galaxies are considerably heavier and their abundance of metals, defined in astronomical parlance as any element heavier than helium, seems higher on average than those of the Green Peas.

In her team’s new study, Shapley and her collaborators have delineated several properties that contribute to the high star formation rate in the remote Lyman-break galaxies. The team’s study, posted online at arxiv.org, will appear in the August 10 Astrophysical Journal. The researchers were able to study the pattern of emissions from hydrogen, nitrogen, oxygen and sulfur atoms in two remote galaxies in great detail because their light was greatly magnified by a gravitational lens — a massive foreground object that bends and focuses light from background bodies.

The team found that the star-forming regions of the two remote Lyman-break galaxies have densities 10 to 100 times higher than those of most galaxies in the nearby universe. The density of photons energetic enough to ionize hydrogen atoms is also significantly higher, and the researchers infer that the star-forming regions in the Lyman-breaks are under higher pressure.

These factors may dictate that gas collapsing to form stars in these galaxies coalesces into slightly heavier stars on average than the gas in galaxies today does, she suggests.

Shapley says she wishes the authors of the Green Peas paper had taken additional steps to measure some of these physical properties in the newly discovered galaxies._________________Olemmeko löytämässä itse itsemme? Yhdistyvätkö eri uskonnot ja tiede jo meidän aikana?